ON THE LICHEN-GONIDIA QUESTION. 
261 
accepted, would virtually deprive lichens of the position which 
had hitherto been assigned them in the vegetable kingdom. 
For though the name might still be retained for the sake 
of convenience, or of old associations, it would serve no longer 
to convey to our minds the notion of a distinct class of plants, 
but only to remind us of its degradation from a position once 
as high and apparently more stable than that held either by 
the algae or the fungi. 44 Lichenes fuerunt ; algo-fungi modo 
sunt.” 
The theory referred to, and now well known as the 44 Schwen- 
denerian hypothesis,” has been favourably received by various 
continental cryptogamists, and has given rise to a very 
considerable amount of discussion. No lichenist, however, 
has as yet given it any support ; nor, judging from present 
appearances, is at all likely to do so. It may very succinctly 
be stated thus : — Lichens are not autonomous plants, but are 
composed of an algal and a parasitic fungus. This singular 
hypothesis, which if well founded would be entirely subversive 
of all previous conceptions of the nature of lichens, was first 
made public by Professor Schwendener in 1868, towards the 
conclusion of a paper entitled 44 Untersuchungen fiber den 
Flechtenthallus.” According to the view here propounded, 
each individual lichen is to be considered as an algal-type which 
has become the host of a parasitic fungus-growth ; whence it 
follows that these algae, under the name of 44 gonidia,” have 
hitherto been erroneously regarded by cryptogamists as special 
organs of lichens. In a subsequent paper, published in 1869, 
64 Die Algentypen der Flechten gonidien,” he expresses his 
views at still greater length, and endeavours to strengthen 
and amplify his theory by various arguments founded upon 
personal observation. To render the theory more intelligible, 
and to prepare the way for entering into details, it may be 
well to give the general conclusion which he arrives at in his 
own, and, in this instance, somewhat pictorial language. 44 As 
the result of my researches,” he says, 44 all these growths are not 
simple plants, not individuals in the usual sense of the term ; 
they are rather colonies, which consist of hundreds and thou- 
sands of individuals, of which, however, only one acts as master, 
while the others, in perpetual captivity, provide nourishment 
for themselves and their master. This master is a fungus of 
the order Ascomycetes , a parasite which is accustomed to live 
upon the work of others ; its slaves are green algae, which it 
has sought out, or indeed caught hold of, and forced into its 
service. It surrounds’ them, as a spider does its prey, with a 
fibrous net of narrow meshes, which is gradually converted into 
an impenetrable covering. While, however, the spider sucks 
its prey and leaves it lying dead, the fungus incites the algae 
